Evaluation of multiple disease resistant common bean (Phaseolus vulgaris L.) lines for adaptability and disease resistance across diverse agroecological zones in Kenya

Kenya Agricultural & Livestock Research Organization

The common bean breeding team at KALRO Kakamega, from left to right: Mr Fred Mulusa, Ms Philomena Mwanganyi, Mr Shamir Misango, Mr Shadrack Odikara and Ms Sheila Chepkurui

PROJECT OVERVIEW

Background

The project aims to evaluate common bean lines developed through a backcross breeding programme involving four parent lines: MCM 2001, used as a donor for resistance to Bean Common Mosaic Virus (BCMV) and Bean Common Mosaic Necrosis Virus (BCMNV); VAX3, as a donor for resistance to common bacterial blight (CBB); G2333, as a donor for anthracnose resistance; and CAL194, the recurrent parent, which is resistant to Pythium root rot.

Project overview

The KALRO team scoring for disease resistance in field trials.

Institute of Agricultural Research Training (IAR&T), Ibadan Nigeria

The IAR&T cowpea breeding team. Left to right: Mr Adanikin Bamidele, Mr Akintunde Adewole, Dr Olaniyi Oyatami and Dr Adenike O. Dada.

Objectives

To evaluate the disease resistance of common bean lines against BCMV, BCMNV, CBB, Pythium root rot, and anthracnose under greenhouse conditions.
To screen common bean lines for disease resistance using molecular markers.
To evaluate the adaptability of common bean lines across different agro-ecological zones in Kenya.

Progress to date

Diseased plant samples were collected from the Western region of Kenya, and isolates were obtained for assessing the resistance of common bean breeding lines through artificial inoculation experiments.The lines have been screened for resistance to common bacterial blight (CBB) and anthracnose under artificial inoculation conditions. Testing for resistance to Pythium root rot is currently underway.
Molecular screening and evaluation of the breeding lines using SCAR markers is also in progress.
Multi-location field trials were established in April 2025 across key bean-growing regions identified as disease hotspots. Disease scoring in the field has been conducted at two critical growth stages (vegetative and flowering) using the standardised CIAT 1-9 disease severity scale. Preliminary data indicate variable resistance responses among the tested lines, with certain genotypes exhibiting promising resistance levels. Evaluation at the pod-filling stage is scheduled to be completed in the coming weeks, enabling comprehensive profiling of disease responses across developmental stages.